Televes Televes
Language: en | es

NOT 519-2002-en




the amplifier maximum output level determines the maximum level that an amplifier can deliver without saturation.

an amplifier is saturated when, at given increments of its input level, its output is not incremented in the same proportion than its own gain and it therefore undergoes compression.

when an amplifier undergoes this situation, it means that it is working out of its linear response zone.

because of this, there are three distortion types that can be produced:

  •  intermodulation ( the distortion of the tv signal within the channel).
  • cross modulation (carrier overmodulation due to another modulated signal).
  • channel carrier harmonics that can appear inside another channel.

how to calculate the maximum output level of the amplifier

manufacturers' catalogues use to make allusions to standard din 4500 4b (une 20-523-79 part vi).

this standard explains how the specific maximum output level for either a broadband or a single channel amplifier is calculated.

  • single channel amplifiers
  • for single channel amplification,three carriers are generated (figure 1).
    they are applied to the amplifier.
    then its input level is increased to obtain an output frequency spectrum, as the one shown in figure 2.

    when the intermodulation product achieves a dm value equal to 54 db, the maximum output level will be that indicated in fig. 2.

  • broadband amplifiers
  • in these kind of amplifiers, three carriers, f1, f2 and f3, are generated, as shown in figure 3.
    afterwards, these three carrier levels are increased (the three of them at the same time) to obtain the amplifier output frequency spectrum, as shown in fig. 4.

    when the cross modulation product achieves a dmc value equal to 60 db, the output maximum level specified for this particular amplifier will be the one indicated in fig. 4.

    in broadband amplifiers, when there are more than two input channels this implies that the reduction tables have to be applied to the output level.

    these tables can be found attached to all our product catalogues.

    Id Anrterior: 
    Televes Televes